The present invention relates to the cycle industry. It relates to a bicycle wheel hub with adjustable bearing play, and more particularly to an adjusting and locking device for the mounting of such a hub.
A bicycle wheel hub normally comprises a tubular body supported in rotation by the intermediary of two ball bearings on an internal traversing shaft which is at least partially threaded.
Furthermore and often, the tubular body forms a cross-piece between the outer bearing rings and the clearance of the bearings can be adjusted by means of a slight axial displacement of at least one of the inner bearing rings which are screwed or which are made to slide on the traversing shaft towards the mean plane of the wheel.
After adjusting the clearance, the inner ring which has been displaced must be immobilized and this immobilization is frequently obtained by means of a nut/lock-nut system where the nut and the lock-nut are both screwed on the shaft and locked against each other. Now this method has disadvantages which will be explained below. In this explanation, a distinction will be made between the inner and outer sides of the thread of the shaft which are respectively oriented towards the mean plane of the wheel and towards the outside of the wheel. During the adjustment, the nut which pushes the balls towards the inside of the hub bears on the inner sides of the thread of the shaft; on the contrary, after locking, the nut which is itself pushed towards the inside by the lock-nut, locks onto the outer sides of the thread of the shaft.
Between the adjustment phase and the locked phase, the nut has therefore changed bearing sides; now, the axial play of the nut on the shaft is not zero and the change of bearing sides implies an axial displacement of the nut towards the inside of the hub. This displacement modifies the initial adjustment and risks causing an excessive tightening of the balls which, as is well understood, would be harmful to the smoothness of rolling and to the service life of the mechanical elements. In practice, in order to avoid such excessive tightening, a process of trial and error is often carried out by leaving a certain clearance during% adjustment which is intended to disappear when locking the nut/lock-nut system. Adjustment by trial and error is a waste of time and, furthermore, it is not within everyone's capability and for a piece of machinery as widespread among the public as the bicycle, it can be expected that there is a high number of hubs incorrectly adjusted and having either an excessive clearance or an excessive tightening.